Let me put it this way...I had to stick my 1C's in a 12x12 room because my basement was not finished. It was not that great..at all, they sounded ok..but if you tried to put it up to 10:30 or 11 on the pre....they were just not very good at all..as long as you played them at low volume...there fine.
When i got the basement finished....17x30..took all the speakers and equipment down there....plugged in the 1C's...now this is the same equipment..nothing has changed...
The speakers were massive.....you want Allman live..you have it..at about 10:30 on the volume..you push it to 11...your getting your brain kicked along with your stomach.
The difference in room size was massive...thats all i can tell you..if you don't by it..well thats all i can say.
Room acoustics only do so much..if you try and drive large speakers at large volumes..then the room size means alot.